NORONET

Noronet is a global network of scientists working in public health institutes or universities sharing virological, epidemiological and molecular data on the norovirus.

Global Noronet

Noronet is a global network of scientists working in public health institutes or universities sharing virological, epidemiological and molecular data on norovirus. The aim of Noronet is to enlarge the knowledge on geographical and temporal trends in the emergence and spread of Norovirus variants, thus limiting the impact and scale of future norovirus epidemics. A second aim is the design of a well-founded standardized nomenclature for existing and emerging norovirus genotypes and variants or sub-lineages. By prospectively sharing information on norovirus activity we can chart the global spread, recognize changes in circulating strains and possible changes in the epidemiology of the virus and thus potentially predict epidemic seasons

Global Noronet is coordinated by professor Marion Koopmans and Miranda de Graaf from the department of Viroscience of ErasmusMC and Harry Vennema and Annelies Kroneman from the RIVM. If you are interested in joining the NoroNet laboratory network, or have any questions, please mail to noronet@rivm.nl. Membership allows you to access the molecular epidemiology database and analysis tools and involves the signing of a confidentiality agreement (pdf).

Typing tool

In order to ensure standardized typing of the sequences, all submitted sequences are typed using the publicly accessible norovirus typing tool on the website of the RIVM.

Below you can find an overview of the polymerase and capsid genotypes that members have reported to NoroNet for genogroup I (GI) and II (GII) from January 2015 until June 2018. Figures 1 to 7 show the data for the polymerase and capsid genotypes per year and per country. For GI we see co-circulation of several capsid and polymerase genotypes (Figure 1, Figure 5 and 7).

Figure 1 GI Polymerase and Capsid genotypes per year

For GII the most prevalent polymerase genotypes are GII.P4 Orleans 2009, GII.Pe, GII.P17 and GII.P16 (Figure 2, Figure 6). The polymerase GII.P16 has circulated for years with different capsid genotypes, but in the past years it became the predominant polymerase genotype and is mostly found in combination with the capsid genotypes GII.4 Sydney 2012 and GII.2 (Table 1.).

Although there are many GII capsid genotypes co-circulating there are large differences in prevalence. GII.4 variant GII.4 Sydney 2012 is still the most prevalent genotype (Figure 3, Figure 4 and Figure 7). For GII.17 there was a major increase in prevalence in 2015 and 2016, currently GII.17 outbreaks are still reported but at a lower frequency. For GII.2 there is also an increase in prevalence, mainly of GII.2 in combination with the GII.P16 genotype (Table 1).

Figure 2 Polymerase GII genotypes per year

Figure 3 GII Capsid genotypes per year

Figure 4 GII.4 variants, capsid and polymerases. *For GII.P16 all sequences were included including GII.P16 sequences that were detected in combination with a non-GII.4.